Count fish in a catch from a photo

Counting fish on a sorting table, a tray or at the landing

Fishers tally a catch on deck or at the landing, hatcheries count fingerlings for stocking, and market traders count a lot before sale. All of them get the clearest result where fish lie still in one layer: a sorting table, a fish box or a shallow tray. For fingerlings, a white tray with a little water spreads small fish apart against a plain background.

Wet scales reflect light, so a strong overhead lamp or flash can turn one fish into two bright patches; diffuse light or shade works better. Crushed ice hides heads and tails, and fish laid head to tail in overlapping rows merge into one shape, so spread them out before the photo. A mixed catch may need one example per species, up to three, with the Found per example list giving a figure for each. Fish in a pond or tank overlap and refract, so count them at transfer or harvest as they pass through trays or graders.

This page counts fish; it does not measure length or weight. Add each tray or box as a tally row and correct any misses before the total goes into a catch or stocking record, which may still need your usual verified method. Boxed catch stacked on the quay can be handled with the crate counter, and other small items on a tray suit the general object counter.

Setting up a tray or table photo

• Fish in a single layer, not overlapping head to tail
• Ice pushed aside so heads and tails are visible
• Diffuse light instead of a flash straight down on wet scales
• One example per species when the catch is mixed